If there is one single factor that distinguishes successful from unsuccessful entrepreneurs then it is not luck, charm, tech chops, timing or a host of other factors. It's persistence.

You're definitely showing persistence, the fact that it hasn't paid off yet is not a reason to give up now or to tell others to give up. What you probably could do is to evaluate your own application against the companies that got picked in previous cycles and ask yourself what if any differences there are, if you are maybe lacking some other crucial ingredient.

But kudos on the persistence, if you just start to execute on one of your ideas and you maintain that level of persistence there is a good chance that at some point you will see some return for your work.